Structure updates

The initial publish process moves all dimensions as they currently appear in IBM® Cognos® Controller.

As it is possible to store measures on aggregation nodes in IBM Cognos Controller, but not in TM1®, the structure update process needs to manage both aggregation nodes as well as dimension changes. For more information, see Dimension transformation principles.

The structure updates process consists of two parts:

  • Publish children - structures are automatically moved to TM1 for the fact trickle to work.
  • Update structures - the TM1 dimensions are re-generated. This is done manually by the user in the FAP client.

Workflow for the first part of the structure updates:

  1. Based on the clock interval defined in the FAP client, the FAP Service searches for changes in the IBM Cognos Controller database.
  2. The FAP Service transfers structural changes from the IBM Cognos Controller database to the FAP database.
  3. The FAP Service calls the TM1 API and initiates a TI script.
  4. Members are added in the TM1 dimensions. The cube can be reported on but is not updated during this operation.
Note: At this point new members are not inserted in the right place in the TM1 hierarchy. This is done in the second part of the update.
Figure 1. Structure update process, structural changes transferred
The FAP service searches for and transfers structural changes from the Controller database to the FAP database. Members are added to TM1 dimensions in the FAP cubes.

Workflow for the second part of the structure updates:

  1. The user notices that there are pending dimension updates in the FAP client.
  2. The user initiates the structure update in the FAP Client.
  3. The FAP Service transfers structures from IBM Cognos Controller to the FAP database.
  4. A TM1 API call is triggered to move updates from the FAP database to the FAP cubes.
  5. Dimensions are updated according to the IBM Cognos Controller hierarchy. Fact and data are kept during this operation.

Users and authorization groups are also handled in this step, which is also seen as slowly moving dimensions. Slowly moving dimensions are dimensions that change infrequently.

The update of slowly changing dimensions is a manual process due to process and technical reasons. A dimensional update could potentially invalidate reports, and even a small change in IBM Cognos Controller could generate costly operations on the TM1 side. Typically, it is beneficial to have a level of user control over this step, for example to collect a number of changes before updating the cube.

Figure 2. Structure update process, TM1 dimensions updated
In the FAP client users start the structure update. The service transfers updates from the Controller database to the FAP database. Updates are then moved to the cubes.